5abivt

Well my 8200 rpm LT4 c4 project is coming to an end and itll probably take a seat in the garage since ive been planning this project for a while now.

Basic details are:

Cyber Grey c6z06
HRE monoblock wheels
Coil overs
Destroked LS7 to 5-XL ?

After sitting on some Ford stock for a while now I have a burning in my pocket and the wife has given the green light to go a little crazy.

Any thoughts on building an ls7 for 8500 rpm?

Im planning to destroke to keep piston speed down. I will leave final details in the hands of the builder who I haven't chosen as of yet. Billet lightweight crank, Ti or billet lightweight rods, nto sure what heads to go with yet. Manifold will probably be an individual throttle body wilson. Im thinking to try and go for c5r dual 'lung' style manifolds although I think hood clearance is an issue and I despise any raised hoods offered.

Goal is to have peak torque at 7000 rpm. This will be a highway rocketship that will make people go deaf at high rpms

Joe_Planet

whats the goal here exactly?

NORTY

Valve gear is going to be your largest issue, beginning with a cam. I'd like to hear the final product though...

Bill Dearborn

Not sure you can make it anymore of a highway rocket ship than it is now. Lots of down low torque so you don't need to downshift. Just push on the gas pedal and it just goes. With a torque peak that high you would have to downshift quite a bit and the engine wouldn't be as tractable as it is now in traffic, etc. Besides, even if you approach it from the I don't care what the law says there is a practicable limit to what you can do on the street or highway. The current Z already far exceeds those practibable limits since it is almost impossible to drive it all out on public thorough fares. Not enough room, poor sight lines, other drivers doing stupid things, blind curves, pedestrians, animals, etc.

Bill

1.8t

You will have a tough time with the transmission at those rpm levels.

OldDominion

Also would need to check into a clutch package, as i am not sure what the speed rating is on that and if the pressure plate would be able to keep an adequate enough clamp load on the disk.

novaz06

I think this is an ambitious project, but I'd love to see it. I don't think anyone has even done 8000 rpm on these engines. You'll probably need a shaft mounted rocker solid roller cam setup. I'd shoot for 8000 rpm with the stock stroke. That would an amazing engine.

What is 5-XL?

5abivt

I left out much of the minor details but If figured it would just be std fare for these rpms like my LT4. Shaft rockers, hollow or ti valves, solid roller cam and the best of the best pushrods and solid roller lifters. The cam will be aggressive as possible and I understand asking for a 6000-8000 rpm power curve means not much driveability which is fine by me. i want the cam so aggressive i dont mind it being borderline untuneable at low rpms. I want this to be a race car on the street pretty much.

I dont intend to drag it so im not too worried about the tranny i dont plan to shock it by powershifting but those rpms will surely need a strong clutch. The usual bolt ons will be std fare. mezziere pump, underdrive pullies and ati damper so my accessories dont explode at those rpms. Haven't decided on longtubes but no cats and probably a corsa system.

5-xl was just an 'x' for final engine size in Litres. Im not sure if I'll be limited by the bore on the ls7 block I may go aftermarket for a larger bore and cut back on the stroke even more.

Bill I appreciate the comments and you are right but you are telling a guy who has taken his c4 to 208 mph on the street. and over 180 numerous times datalogging. Now I don't plan to drive like that much anymore but high speed acceleration is what I crave. Im not a fan of torque at all i want high rpm screaming.

novaz06

btw can't you go to prison for like 20 years in canada for driving at 200mph on the street?

5abivt

i meant it was at a track

McMung

What part of "make people go deaf" don't you understand?

Polo-1

I don't think the rotating assembly will have problem. It's the top end(cam,lifter,push rods,valves springs). My 402 ci 4.00x4.00 runs 8000rpm all day long with Crower maxi-lite steel rods. It's a LT5 DOHC. The fact that the cams ride on the valve makes it easy for the high rpm.

Turbo T/A

Exactly.....not sure why you'd like to build an "8500" rpm pushrod motor? Its just not designed for that & wont live long "highway driving" it.

You know, i read some of these threads & wonder how thick the glasses are or how high those socks are pulled up.

RPM kills motors - period. There is no replacement for displacement - period. You want a highway "rocket" then build a good motor, not an "8500 rpm" motor.

BTW, i shifted my TT 400" sbc in my old '69 T/A at 6500 rpm...it trapped 164mph in the 1/4 and had a $hitload of jam on the highway (3.00 gear). You need horsepower, not RPM....there is a difference!

-Carm

Mopar Jimmy

Here we go.

IanM

What is the goal here? The car turns 7k and makes more power and most importantly more torque than the foreign stuff. If you want a high rpm engine buy a Ferrari right? Those guys brag about how their cars turn crazy RPM and make the same power we do on less displacement yet the make far less torque and even though it isn't really relevant get worse MPG on a smaller displacement engine. IMO that is complete and utter FAIL. In the end what you come out with is this...

Z06- Turns 7k RPM with big displacement makes more torque and overall power and gets better MPG and wins races.

High Revs- Turns higher RPM and sounds different... end of story. Every other aspect it loses.

That is just my .02

EDinPA

camirocz

Why would you ruin a prefectly good driving car by taking away most of its driveability?It does 198 mph in stock form you going after the Buggati Veyron?Seriously do a heads and cam package and have fun with your car.Too much is overkill and by the sound of it you d be ruining a perfectly good car.

avalonandl

8000rpm: You essentially want turn your LS7 into a NASCAR motor who routinely see 9200 rpm. The way to approach this is to take an LSX block and build it to fit in your Z06. The LS7 motor is to valuable to try to retrofit it IMHO but that is your choice.

Definitely you need billet rods and crank, a new intake design, solid roller cam and probably the NASCAR cylinder heads. Use NASCAR bore and stroke, don't reinvent the wheel.

Good luck

Avalon

GARY2004Z06

Here is the vid of Robz's Destroked LS7 on the dyno at 9000 rpm.

http://www.youtube.com/watch?v=PaxE6dsfb_o

This build took a great deal of R&D and is not for the faint of heart.

Mopar Jimmy

THere you go, pefect example of how to do this in one of most successful drag racer's car, Robz's, 9 second n/a C5.

Hope you have some BIGGGGGGGG $!